1. Field of the Invention
The field of the invention relates generally to locking devices and particularly to a locking device for electrical appliances and electrical power tools having a male electrical plug in order to prevent the unwanted use of said appliances or tools.
2. Description of Related Art
Common electrical appliances such as computers, televisions, toasters and microwave ovens often need protection from unauthorized use. Further, electrical power tools such as electric drills and saws can be hazardous if left unattended. Protection may often be best obtained through a locking device that is made operational by a key. This protection could be used to prevent children from using dangerous appliances, or handling unprotected electrical power tools or to prevent unauthorized use of the appliance in places such as electronics stores. While there are several possible solutions to the problem, a simple, easy-to-manufacture device is needed which has a minimal number of moving parts.
Other locking devices for electrical devices are known. U.S. Pat. No. 6,142,797 issued to Bailey teaches a device that uses oddly shaped functional components in its interior that would be difficult to manufacture and could easily break. Also, U.S. Pat. No. 6,159,025 issued to Derman teaches a lock. However, the Derman reference requires a sturdy cable through the body. In addition, U.S. Pat. No. 5,666,829 issued to Aikens teaches a plug lock. However, in the Aikens device, a bolt spreads the prongs of the plug. Over time, the spreading of the prongs of the electrical plug would cause significant damage to the device. Also, U.S. Pat. No. 5,507,656 issued to Ales requires several moving parts that may break, and an extra securing device such as a padlock. Ales requires two springs, a coil spring and a flat spring, thereby unnecessarily increasing the cost of production. Also, Ales, includes a bulky and unwieldy plunger to release the device from the lock.
The prior art inventions are flimsy, bulky, and expensive or require additional, unnecessary parts in their manufacture. Accordingly, what is needed is a lock for a male electrical plug that is simple and easy to manufacture. A need also exists for a lock with a minimum of moving parts. In addition, a lock is needed which will secure the electrical device and prevent its unwanted use while not damaging the plug or the device itself.
The instant invention has been directed to the effective resolution of the aforementioned shortcomings and to the meeting of the aforementioned needs.
The present invention provides a novel and unique compact locking device for securing and locking an appliance""s electrical power cord plug thereby preventing the unwanted use of the appliance.
The present invention is compact, lightweight and easy to manufacture. The present invention will secure an electrical appliance with a minimal number of moving parts. Also, the present invention is easier and less costly to manufacture than the prior art, and has none of the fragile pieces found in the prior art.
The present invention is a compact locking device for securing a male power cord plug having a plurality of prongs, the device comprising a body member having one or more plug-receiving apertures for receiving the prongs of the plug, each prong containing one or more holes, means for rotatably receiving a portion of a key, a rotatable member situated within the body member capable of rotating from a first disengaged position to a second engaged position, the rotatable member rotating in the same direction as the rotation of the key, and means for engaging the holes of the prongs upon rotation of the key thereby preventing the prongs from being withdrawn from the body member.
In a preferred embodiment, the locking device comprises a body member having one or more plug-receiving apertures for receiving the prongs, each prong containing one or more holes, a key-lock mechanism within the body, the key-lock mechanism including a channel for receiving a portion of a key, the key capable of being rotated within the channel, and a spring member secured within the body member, the spring member having two outer arm members, each outer arm member having a knob disposed upon its outer edge wherein the elongated member is positioned between the outer arm members. The key-lock mechanism further comprises an elongated member wherein the elongated member rotates from a first substantially parallel position with respect to the arm members, to a second substantially transverse position with respect to the arm members, the elongated member rotating in the same direction as the rotation of said key. Upon rotation of the key within the channel, the elongated member is rotated from the first to the second position thereby biasing the outer arm members outward. Upon the outward biasing of the arm members, the knobs of the spring member cooperatively engage the holes in the prongs of the plug thereby preventing the prongs from being withdrawn from the body member.
In an alternate embodiment of the invention, the plug-receiving apertures are located on the body member such that a ground fault disrupter prong on the plug would be located outside the device when the prongs are inserted within the apertures. In an alternate embodiment, the body member further comprises an opening to accommodate the ground fault disrupter prong in the plug.
The present invention is also a method for securing a male power cord plug with prongs having holes within a body member, comprising the steps of inserting the prongs of the plug within one end of the body member, inserting a key within another end of the body member, upon rotation of said key, outwardly biasing two outer arm members of a spring, the spring affixed within the body member, wherein each outer arm member has a knob thereon whereby upon rotation of the key within the body member, the knobs of the spring cooperatively engage the holes in the prongs of the plug thereby preventing the prongs from being withdrawn from the body member.
In a further embodiment of the present invention, a compact locking device is provided for securing a male power cord plug with prongs having holes. The locking device comprises a rigid plastic body with an interior and an exterior, a top, a bottom, a front, a back, a left and a right side, wherein each side has an inner and outer surface. The body includes two apertures on the back side of the body, each aperture for accommodating one of the prongs, a key-activated lock assembly accessible on the front side of the body for locking and unlocking the plug, an elongated member cooperatively attached to the lock-activated assembly, the elongated member rotatable to a transverse position in relation to the plug when the lock assembly is engaged, and an inwardly biased generally V-shaped spring with a base and two outer arm members, each outer arm member having an outside section and a circular knob thereon. The base of the spring is attached to the inner surface of the body, and the knobs are in cooperative connection with the holes in the prongs when the lock-activated assembly is engaged. The knobs are released from the holes in the prongs when the lock-activated assembly is disengaged. The apertures are located so that a ground fault disrupter on the plug would be located outside the device when the prongs are within the apertures.
It is an object of the invention to provide an easy-to-manufacture locking device for a male electrical plug in order to prevent the unauthorized use of electrical appliance and/or electrical power tools.
It is also an object of this invention to provide a locking device with a minimal number of moving parts.
It is to be understood that both the foregoing general description and the following detailed description are explanatory and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate embodiments of the present invention and together with the general description, serve to explain principles of the present invention.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.